Extracorporeal membrane oxygenation (ECMO) is a drastic treatment applied to critically ill near term neonates in severe cardiorespiratory failure. The survivors represent a unique population of children who would have died prior to the introduction of the procedure, and who have a high probability of having sustained neonatal brain trauma. Given the severity of illness among ECMO candidates prior to treatment with ECMO cannulation, and the risks inherent in the procedure, the evidence attests to the remarkable potential of the developing brain to adapt to such insult. However, only limited research is available regarding the survivors, and the use of the procedure is rapidly expanding. Short term follow-up is sufficient for major handicap only. The one published longterm study contained only 16 children. We propose a follow-up of 150 children at 5 years of age from our current cohort who were treated with ECMO as neonates. All had routine neuroimaging in the newborn period. Performance will compared to a control group of 50 normal, healthy 5-year old children. Sex, race, and maternal level of education will be controlled. A comprehensive multidisciplinary approach to assessment will be employed, with both standard, broad-based techniques to evaluate major handicap, and more focused and detailed assessments to document performance in areas of auditory/linguistic or visual/perceptual skills, sensory-motor integrity, attentional and behavioral problems, and neuromotor dysfunction. The significance of this research is that it will evaluate the longterm neurobehavioral morbidity among a large cohort of ECMO survivors as they approach school age. The findings will also contribute to understanding the consequences of brain lesions in near term neonates.